Over the last few years remarkable efforts have been made using functional imaging studies to unravel brain processing of pain and decipher underlying neuronal mechanisms. Cerebral processing in ...experimental pain models, especially those provoking hyperalgesia, and its pharmacological modulation will form the first part of this review. In a second part we will address central mechanisms of clinical neuropathic pain. Up to now, there are at least six main mechanisms involved in the chronification of neuropathic pain: (i) activity increase in areas of the pain neuromatrix, (ii) recruitment of additional cortical areas beyond the classical pain neuromatrix, (iii) cortical reorganization and maladaptive neuroplasticity, (iv) alterations in neurochemistry (v) structural brain changes and (vi) disruption of the brain default mode network. In a third part of this review we discuss mechanisms of endogenous pain modulation.
Moiré heterostructures of transition metal dichalcogenides (TMDs) exhibit Mott-insulating behavior both at half filling as well as at fractional fillings, where electronic degrees of freedom form ...self-organized Wigner crystal states. An open question concerns magnetic states obtained by lifting the pseudospin-1/2 degeneracy of these states at lowest temperatures. While at half filling virtual hopping is expected to induce (weak) antiferromagnetic exchange interactions, these are strongly suppressed when considering dilute filling fractions. We argue that, instead, a small concentration of doped electrons leads to the formation of spin polarons, inducing ferromagnetic order at experimentally relevant temperatures, consistent with recently observed ferromagnetic states in moiré TMD systems. We predict explicit signatures of polaron formation in the magnetization profile.
We study transitions between topological phases featuring emergent fractionalized excitations in two-dimensional models for Mott insulators with spin and orbital degrees of freedom. The models ...realize fermionic quantum critical points in fractionalized Gross-Neveu* universality classes in (2+1) dimensions. They are characterized by the same set of critical exponents as their ordinary Gross-Neveu counterparts, but feature a different energy spectrum, reflecting the nontrivial topology of the adjacent phases. We exemplify this in a square-lattice model, for which an exact mapping to a t-V model of spinless fermions allows us to make use of large-scale numerical results, as well as in a honeycomb-lattice model, for which we employ ε-expansion and large-N methods to estimate the critical behavior. Our results are potentially relevant for Mott insulators with d^{1} electronic configurations and strong spin-orbit coupling, or for twisted bilayer structures of Kitaev materials.
An ultra-stable, high-power cw Nd:YAG laser system, developed for the ground-based gravitational wave detector Advanced LIGO (Laser Interferometer Gravitational-Wave Observatory), was comprehensively ...characterized. Laser power, frequency, beam pointing and beam quality were simultaneously stabilized using different active and passive schemes. The output beam, the performance of the stabilization, and the cross-coupling between different stabilization feedback control loops were characterized and found to fulfill most design requirements. The employed stabilization schemes and the achieved performance are of relevance to many high-precision optical experiments.
Researchers at the National Institute of Standards and Technology (NIST) have measured the value of the Planck constant to be h=6.626069934(89)×10−34J s (relative standard uncertainty 13×10−9). The ...result is based on over 10 000 weighings of masses with nominal values ranging from 0.5 kg to 2 kg with the Kibble balance NIST-4. The uncertainty has been reduced by more than twofold relative to a previous determination because of three factors: (1) a much larger data set than previously available, allowing a more realistic, and smaller, Type A evaluation; (2) a more comprehensive measurement of the back action of the weighing current on the magnet by weighing masses up to 2 kg, decreasing the uncertainty associated with magnet non-linearity; (3) a rigorous investigation of the dependence of the geometric factor on the coil velocity reducing the uncertainty assigned to time-dependent leakage of current in the coil.
Complex regional pain syndrome (CRPS), formerly known as Sudeck’s dystrophy and causalgia, is a disabling and distressing pain syndrome. We here provide a review based on the current literature ...concerning the epidemiology, etiology, pathophysiology, diagnosis, and therapy of CRPS. CRPS may develop following fractures, limb trauma or lesions of the peripheral or CNS. The clinical picture comprises a characteristic clinical triad of symptoms including autonomic (disturbances of skin temperature, color, presence of sweating abnormalities), sensory (pain and hyperalgesia), and motor (paresis, tremor, dystonia) disturbances. Diagnosis is mainly based on clinical signs. Several pathophysiological concepts have been proposed to explain the complex symptoms of CRPS: (i) facilitated neurogenic inflammation; (ii) pathological sympatho‐afferent coupling; and (iii) neuroplastic changes within the CNS. Furthermore, there is accumulating evidence that genetic factors may predispose for CRPS. Therapy is based on a multidisciplinary approach. Non‐pharmacological approaches include physiotherapy and occupational therapy. Pharmacotherapy is based on individual symptoms and includes steroids, free radical scavengers, treatment of neuropathic pain, and finally agents interfering with bone metabolism (calcitonin, biphosphonates). Invasive therapeutic concepts include implantation of spinal cord stimulators. This review covers new aspects of pathophysiology and therapy of CRPS.
Upgrade plans for the ATLAS calorimeters Seifert, F.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2013, Letnik:
718
Journal Article
Recenzirano
The ATLAS calorimeter is composed of detectors based on different techniques to exploit the best performance while maintaining a sufficient radiation resistance. A radiation resistant liquid argon ...(LAr) sampling calorimeter is used for all electromagnetic sections, for the endcap (HEC) and forward (FCal) hadronic sections. The most central hadronic section is, instead, a steel–scintillator sampling calorimeter (TileCal). Plans are already being developed for operation of the LHC and the detectors at an increased instantaneous luminosity about 5 times the original design value. There are plans for a two-phase detector upgrade. For Phase I, the LAr calorimeter trigger will be upgraded. For Phase II, the TileCal upgrade consists in replacing the on- and off-detector electronics and for the LAr system includes changes to the DAQ, the HEC cold electronics and the FCal. Development work for these options includes high rate tests of small test modules of the endcap and forward detectors.
The vast majority of terrestrial plants exchange nutrients with fungal partners forming different mycorrhizal types. The minority of plants considered as non‐mycorrhizal, however, are not necessarily ...free of any fungi, but are frequently colonized by elusive fungal endophytes, such as dark septate endophytes (DSE) or fine root endophytes (FRE). While a functional role of FRE in the improvement of nutrient gain was recently elucidated, the function of DSE is still in discussion and was here addressed for 36 plant species belonging to the families Equisetaceae, Cypereaceae and Caryophyllaceae.
Molecular and microscopic staining approaches were conducted to verify the presence of DSE in the investigated species. Stable isotope natural abundances of the elements carbon, nitrogen, hydrogen and oxygen and total nitrogen concentrations were analysed for the respective species of the target plant families and accompanying mycorrhizal and non‐mycorrhizal (Brassicaceae) plant species.
Staining approaches confirmed the presence of DSE in all investigated species within the families Equisetaceae, Cyperaceae and Caryophyllaceae. A co‐colonization with Paris‐type arbuscular mycorrhiza (AM) was occasionally found by staining and molecular approaches in species of the Equisetaceae. Species of the Equisetaceae, Cyperaceae and Caryophyllaceae were significantly 15N‐enriched in comparison to accompanying plants. In addition, a significant 13C and 2H enrichment and increased total nitrogen concentrations were found for representatives of the Equisetaceae.
The 15N enrichment found here for representatives of Equisetaceae, Cyperaceae and Caryophyllaceae provides evidence for a functional role of the ubiquitous DSE fungi. DSE fungi obviously provide access to 15N‐enriched soil organic compounds probably in exchange for organic carbon compounds from plant photosynthesis. As indicated by additional 13C and 2H enrichments, representatives of the Equisetaceae apparently gain simultaneously organic carbon compounds from their AM fungi of the Paris‐morphotype. Thus, species of the Equisetaceae have to be considered as partially, or in case of the achlorophyllous fertile Equisetum arvense, as fully mycoheterotrophic at least in some stages of their life cycle.
So far, mostly underappreciated fungi classified as DSE are suggested to occupy an ecologically relevant role similar to mycorrhizae and the occurrence of simultaneous functions of DSE and AM fungi in Equisetaceae is proposed.
A free Plain Language Summary can be found within the Supporting Information of this article.
A free Plain Language Summary can be found within the Supporting Information of this article.
We search for a spin-dependent P- and T-violating nucleon-nucleon interaction mediated by light pseudoscalar bosons such as axions or axionlike particles. We employ an ultrasensitive low-field ...magnetometer based on the detection of free precession of colocated 3He and 129Xe nuclear spins using SQUIDs as low-noise magnetic flux detectors. The precession frequency shift in the presence of an unpolarized mass was measured to determine the coupling of pseudoscalar particles to the spin of the bound neutron. For boson masses between 2 and 500 μeV (force ranges between 3×1(-4) m and 10(-1) m) we improved the laboratory upper bounds by up to 4 orders of magnitude.
PDF
